The relationships between deglutition and respiration will be studied using preparations of fetal and newborn lambs. Particular experiments will be directed at evaluating the deglutition reflex initiated by presence of fluid in the supralaryngeal region to ascertain its effects on suppression of respiration. The circulatory effects of such respiratory suppression will also be studied. The methods proposed will also permit simulation of clinical states in which such reflexes may be important, including neonatal apnea, apnea with feeding in prematures, drug-induced depression of the central nervous system, regurgitation, and gastric dilatation. An hypothesis that such reflexes may be involved in sudden death syndrome of infancy will be evaluated.